The present invention relates to a piston and cylinder assembly. It finds particular application in conjunction with a piston assembly used as a compressor unloader piston and will be described with particular reference thereto. It will be appreciated, however, that the invention is also amenable to other applications.
A compressor unloader piston assembly includes sealing members (e.g., o-rings, quad rings, and/or cap seals) that provide a seal against the cylinder bore wall and may also guide the piston within a cylinder bore. Side forces exerted on the sealing members have caused excessive wear on the sealing members and, in addition, piston bore damage. The excessive wear requires replacement of the sealing members earlier than desired. In addition, the damage to the piston bore tends to accelerate wear on the sealing members.
Separate guide features have been used to shield the unloader piston o-rings from side forces. However, separate guides increase manufacturing costs and complexity.
The present invention provides a new and improved apparatus for a compressor unloader piston assembly which addresses the above-referenced problems.